1. Field of the Invention
The present invention relates generally to interior parts for a vehicle, which have a shock absorber equipped with a rib structure.
2. Description of the Related Art
A vehicle comes with various safety measures for passengers. In one safety measure as shown in FIGS. 6 and 7, for example, a pillar garnish 31, which is an interior part of a vehicle that covers a front pillar 10 of the vehicle body, is provided with a shock absorber 60 that has a rib structure.
The pillar garnish 31 is an elongated member bulging toward a passenger compartment 22 at its short-width directional cross section, and is attached to the front pillar 10 by clips 34. As shown in FIG. 7, the shock absorber 60 is provided in space D defined between the pillar garnish 31 and the front pillar 10. The shock absorber 60 includes a plurality of ribs 62 formed on the bottom of the pillar garnish 31, and fulfills FMVSS (Federal Motor Vehicle Safety Standards) 201 (hereinafter, called “Standard 201”).
The shock absorber 60 with a rib structure takes various modes, such as the ribs 62 combined like a lattice as disclosed in Japanese Patent Application Laid-Open No. H10-310009, and the ribs 62 extending in the short-width direction of the pillar garnish 31 and aligned at intervals therebetween in the longitudinal direction as disclosed in Japanese Patent Application Laid-Open No. 2000-318543.
When an impact caused by an accident or the like is applied to the pillar garnish 31, the edges of the ribs 62 of the shock absorber 60 which face the front pillar 10 abut on the front pillar 10 and are supported thereby. At this time, impact force is further applied to the ribs 62 with the edges being supported by the front pillar 10, so that the ribs 62 are collapsed to absorb the impact. In other words, the ribs 62 should be configured so that the edge of each rib 62 is supported at the front pillar 10 even when an impact is applied to the hit point of the pillar garnish 31, which is defined by the Standard 201, from any direction defined by the Standard 201.
As another safety measure, as shown in FIG. 6 or 7, an airbag unit 70 which protects the head of a passenger may be installed at a portion extending from the front pillar 10 to a roof side 16 of the vehicle body as disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-162201. The airbag unit 70 includes an airbag 72 accommodated in space D defined in the bottom of the pillar garnish 31 and a roof side garnish 18 or a roof lining 20, and an inflator (not shown) disposed at a lower portion of the front pillar 10. When a shock sensor detects an impact of a predetermined value or greater, the inflator is activated and the airbag 72 presses the interior part of the vehicle, such as the pillar garnish 31, deforming the interior part toward the passenger compartment 22. The airbag 72 is inflated to come out from the clearance between the interior part and the vehicle body by the deformation, and unfolded in the passenger compartment 22, covering the side window 24.
As shown in FIG. 7, the pillar garnish 31 provided with the shock absorber 60 that has a rib structure secures space for accommodating the airbag 72 between the front pillar 10 and the edges of the ribs 62 by way of lowering the height of the ribs 62. In this case, when an impact is applied to the hit point of the pillar garnish 31, which is defined by the Standard 201, in the short-width direction of the pillar garnish 31, the ribs 62 are not easily supported by the front pillar 10. In other words, the ribs 62 cannot receive the impact so that the entire pillar garnish 31 is displaced from the front pillar 10 as indicated by the two-dot chain lines in FIG. 7, disabling sufficient shock absorption.
The pillar garnish 31 is attached to the front pillar 10 by the clips 34 provided apart from each other on the inner side of the pillar garnish 31 in the longitudinal direction.
Another pillar garnish structure is disclosed in Japanese Patent Application Laid-Open No. 2005-162201 and FIG. 8 in which the engagement projections 36 provided on the bottom of the pillar garnish 31 are inserted into the engagement holes 12 provided in the front pillar 10 to prevent the pillar garnish 31 from coming off when the airbag is unfolded.
When the pillar garnish 31 receives impact in its short-width direction, the entire pillar garnish 31 is displaced in the short-width direction. Then, stress is concentrated on the engaging portions of the clips 34 and the engagement projections 36 with the front pillar 10, or the engagement-projections of the pillar garnish 31. However, because the clips 34 and the engagement projections 36 are not designed to take the force that acts in the short-width direction of the pillar garnish 31 into account, the clips 34 and the engagement projections 36 tend to be easily deformed or broken, and thus they do not contribute greatly to shock absorption.